1. Technical Field
The present invention relates to an electronic device and a method for manufacturing the electronic device.
2. Related Art
Electronic devices including a functional element, such as an MEMS (micro electro mechanical system), arranged in a cavity disposed on a substrate have been generally known. An MEMS, such as a microvibrator, a microsensor, or a microactuator, is housed in the cavity in an operable state because the minute structure needs to be arranged in such a state that it can vibrate, deform, or perform other motions.
As a method for forming a cavity, JP-A-2009-188785 discloses a forming method in which an MEMS structure is formed on a substrate, an inter-layer insulating layer is formed on the MEMS structure, a first covering layer having through-holes is formed, the inter-layer insulating layer is removed through the through-holes of the first covering layer to release the MEMS structure, and, finally, the through-holes of the first covering layer are covered with a second covering layer.
However, such a problem that the MEMS structure and the first covering layer contact each other sometimes occurs due to an external impact or the like. When the problem occurs, the MEMS structure cannot operate stably, thereby leading to a reduction in reliability. Especially in recent years, the distance between the MEMS structure and the first covering layer becomes short in response to the demand for miniaturization of the electronic devices, which is likely to cause the problem described above.